The purpose of this study is to explore the maximum tolerated dose of E2007 in Japanese patients with refractory partial seizures which are uncontrolled with other anti-epileptic drugs (AEDs). Thirty patients will receive E2007 (dose escalating to the maximum of 12 mg per day). The dose of E2007 will be adjusted during 6 weeks. Subsequently, the dose will be fixed and maintained during 4 weeks.